It depends on how your points are related. If you are trying to calculate all the distances between every combination of the points, then a Distance Matrix service is what you would want to use. Bing Maps has a Distance Matrix service: https://learn.microsoft.com/en-us/bingmaps/rest-services/routes/calculate-a-distance-matrix
If you have a bunch of pairs of points and only need the travel information for the pairs, and not all combination of points, then a more efficient option would be the Azure Maps batch route service. Azure Maps has two variations of this service;
- Synchronous version (limited to 100 routes) which is pretty easy to use: https://learn.microsoft.com/en-us/rest/api/maps/route/post-route-directions-batch-sync?view=rest-maps-2024-04-01&tabs=HTTP
- Asynchronous version (limited to 700 routes) is bit more involved in getting the response: https://learn.microsoft.com/en-us/rest/api/maps/route/post-route-directions-batch?view=rest-maps-2024-04-01&tabs=HTTP
If you just have a really long route that goes through 400 points in sequence, then Azure Maps is also a good option. I would recommend using the POST version of their Route Direction service so that your URL doesn't get too long and exceed browser limits. The Azure Maps route direction service supports up to 150 waypoints in a single request. In addition to that, if some of your points are "supporting points" meaning that you want the route to go through them but not stop there (e.g. kind of like route snapping), this service has no documented limit for supported points and I've used it with thousands (had a customer who wanted to snap GPS traces of garbage truck routes and also see the individual stops of the truck). https://learn.microsoft.com/en-us/rest/api/maps/route/post-route-directions?view=rest-maps-2024-04-01&tabs=HTTP
There is a GET version of the route direction service but it doesn't have an option for supporting points: https://learn.microsoft.com/en-us/rest/api/maps/route/get-route-directions?view=rest-maps-2024-04-01&tabs=HTTP
Azure Maps also has a Route matrix services, similar to Bing Maps: